MathRevolution alone is not enough?

I'm using Math Revolution and I have the Manhattan prep advanced quant book.
MathRevolution alone is not enough to get by, no matter what they say. It teaches you how to make the best possible educated guess, which is actually really helpful, and not a part of other resources I've researched.

I've taken the GMAT twice now, and frankly you cannot learn enough math to get a 51 on this exam. I was a mathematics minor who studied probability theory in depth. I can't do some of these probability questions.
The problem that MathRevolution solves very well is this: the first 1/3 of the exam is so easy that you could get by with a bit of knowledge and an educated guess. The first few times I tried the exam, I forgot some rules or got tripped up on details and never even saw the 49-51 level questions I spent months practicing.

All this is to say, the GMAT is not a math exam. It prizes speed and logic more than creativity and analytical skill. Therefore problem solving is more important than knowing how to find the units digit of 10997347^17. MathRevolution is unique in that it is specifically geared towards problem solving.